Electric heater assembly



Ott. 3l, 1967 L s; Koz-BELT ETAL 3,350,674

ELECTRIC HEATER ASSEMBLY v Filed Feb. 23, 1965 United States Patent O 3,350,674 ELECTRIC HEATER ASSEMBLY Lloyd S. Kozbelt and Donald M. Cunningham, Pittsburgh, Pa., assgnors to Edwin L. Wiegand Company, Pittsburgh, Pa. f Y

Filed Feb. 23, 1965, Ser. No. 434,553 1 Claim. (Cl. 338-316) .ABSTRACT F THE DISCLOSURE A plate connecting the terminal end portions of a surface unit, one portion being securely fixed to the plate andthe other being axially movable through an opening vin the plate, and a band member crimped to said otherterminal end portion and abuttable with the plate.

has its heat-generating portion arranged to provide a plurality of convolutions and its terminal end portions extending in spaced, side-by-side relation for connection into an electrical power circuit. In many modern constructions, `such element terminal end portions are designed to be plugged Yinto a suitable socket carried by the range to automatically establish electrical connections to the element when it is disposed in its normal heating position.

Because of the rather critical spacing between the Velement terminal ends necessitated when such ends are to be plugged into asocket, means have in the past been employed to span the element' terminal ends and maintain them Vin the desired spaced relation. Frequently, such means provides for relative axial movement of the element terminal ends to allow for expansion and contraction of the element during heating and cooling cycles. Unfortunately, however, under certain circumstances, it has been found that the provision for uninhibited relative axial movement of the element terminal ends results in improper electrical connection to one of the element terminal ends when it is plugged into its socket. The elimination of this problem -in a novel and highly effective manner is therefore a principal object of the present invention and the advantages thereof will readily become apparent from a study of the following description and from the drawing appended hereto.

In the drawing accompanying thisv specification and forming a part of this application there is shown, for purpose of illustration, an embodiment which the invention may assume, and in this drawing:

FIGURE 1 is a top plan view of a range-top heating element constructed in accordance with the present invention, Y Y

FIGURE 2 is a side elevational view,

FIGURE 3 is an enlarged, fragmentary elevational view generally correspond-ing to the line 3 3 of FIG- URE 2,

FIGURE 4 is a fragmentary sectional view generally corresponding to the line 4d4 of FIGURE 3, and

FIGURE 5 is an enlarged perspective view of a detail during an early stage of manufacture.

As viewed in FIGURE l, the heating unit therein shown is of the type adapted to be supported by the upper panel of a range or'the like for underlying., and supporting a vessel to be heated; Briefly, such heating unit comprises a heating element 10 formed of an elongated metal tube 3,350,674 yPatented Oct. 31, 1967 ice or sheath filled with compacted refractory material in which is embedded an electric resistor conductor. Such conductor terminates short of the lsheath ends and, connected to respective conductor ends within the tube and projecting beyond respective ends thereof, are respective terminal pins 11. The intermediate portion 12 of the element, i.e. that portion which contains the resistor conductor, is known as the heat-generating portion of the element while the element ends 13 and 14 containing the terminal pins 11 are known as the element terminal ends..

As herein Ishown in FIGURES 1 and 2, the intermediate portion 12 of the element is arranged in a plurality of convolutions to provide a generally plane heating surface on Awhich the vessel to be heated may be disposed. Ex-

tending downwardly and radially outwardly of the innermost and outermost element convolutions as respective element terminal ends 13 and 14, such ends being disposed in spaced, side-by-side relation and extending beyond the Aelement heating surface periphery for insertion within a suitable socket (not shown) which establishes electrical connections to respective terminal pins 11.

Since the element is rather flexible, it is supported from beneath by means known in the trade as a spider. In the present embodiment, a spider 15 is formed of a metalk strip positioned on edge and formed to a generally triangular conguration with a base leg 15.1, inclined legs 15.2 joining to form the apex, and a leg 15.3 extending outwardly from such apex. Loops 16 may, in the usual manner, be welded to the undersides of certain of the element convolutions where they cross over the spider leg 15.3, in this case the outermost convolution and the next to innermost convolution; such loops passing the spider y leg 15.3 and being seated in respective notches 17 in such leg to restrict relative movement of the element and the spider in a direction axially of the spider leg 15.3.

While the loops 16 holding the right side of the element (in theV position of parts shown) and the spider together, the means provided for holding the left side thereof together presently comprises -a strut 18 welded to thespider base leg 15.1 and depending therefrom for abutment with the element terminal end 13. The lower end of strut 18 will preferably be forked to not only restrict relative vertical movement between the element and the spider but also relative horizontal movement therebetween.

From the construction thus far described, it will be evident that the element terminal end 14, since it projects from the outermost element convolution, will tend to be somewhat instable because of the resiliency of the element. Thus, it has been proposed to connect the element terminal ends together so that the spacing therebetween will be maintained. In the present embodiment, an apertured metal strip or connection 19 spans the element terminal ends 13, 14 and is lirmly affixed to terminal end 13.' An oversize aperture 20 (FIGURE 4) passes the terminal end 14 whereby such ter-minal end may move longitudinally of the connector during expansion and contraction of the element during heating and cooling cycles.

In order to prevent excess axial deflection of the element terminal end 14 in one direction, especially as it is inserted into its previously mentioned but not shown socket, element terminal end 14 is provided with a shoulder 21 which is proportioned to abut the connector 19 (see especially FIGURE 4). Thus, the rigidity of the terminal end 13 is transmitted to the terminal end 14 j to limit deection of the latter. In the event the combined Itis an important object of the present invention toV provide a connector between the element terminal ends 13, 14 and a shoulder on the element terminal end 14 -at minimum manufacturing cost; accordingly, the following structure and method have been devised.

As best seen in FIGURE and prior to assembly of the connector 19 with the element terminal ends 13, 14, such connector will be formed from a short length of metal strip as follows: An annular boss 22 will be formed in the connector, such boss projecting from one side of the connector and having an aperture 23 for closely receiving the element terminal end 13. Preferably at the same time boss 22 is formed, a similar annual boss 24 having a central aperature 25, for closely receiving the element terminal end 14, will be formed in the connector 19 in spaced relation with boss 22. Boss 24 differs from 22 in that it is almost completely severed from the connector, 'with the exception of a pair of small unsevered portions 26, leaving the oversize aperture 20.

While the means for forming the connector 19 to the stage shown in FIGURE 5 has not been disclosed, it will be understood by one skilled in the art that the bosses 22 and 24 may be formed by subjecting a short metal strip to a die forming operation wherein such bosses are extruded from one side of the strip.

With the connector 19 formed as shown in FIGURE 5, the connector will be slid over the element terminal ends with the terminal end 13 passing through the boss aperture 23 and the terminal end 14 passing through the boss aperture 25. Note that the bosses 22, 24 will be disposed adjacent the free ends of the element terminal portions.

As best seen in FIGURE 3, boss 22 will be radially inwardly deformed, as at -four circumferentially spaced places 27 to thus crimp the connector securely to the element terminal end 13. Preferably at. the same time, boss 24 will be deformed radially inwardly at a pair of opposed places 28. By suchdeformation of boss 24, the latter will be severed from the connector 19 by rupturing the small pieces 26 previously mentioned and will be crimped to the element terminal end 14 to form the previously described shoulder 21. In deforming the boss 24 .as disclosed at but two opposed places, such boss or shoulder will be deformed radially outwardly at opposed places 29 to provide such shoulder with a transverse dimension greater than that of the connector aperture 20. Accordingly, the shoulder 21 thus crimped to the element terminal end 14 will be unable to pass through the aperture 20 as is clearly shown in FIGURES 3 and 4.

In view of the foregoing it will be apparent to those skilled in the art that we have acomplished at least the principal object of our invent-ion and it will also be apparent to those skilled in the art that the embodiment herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specically described; hence it will be appreciated that the herein disclosed embodiment is illustrative only, and that our invention is not limited thereto.

We claim:

In an electric heater assembly ywherein an elongated, metal-sheathed electric resistance element has a convoluted, intermediate heat-generating portion providing a generally flat heating surface and terminal end portions connected to and extending from said intermediate por tion in spaced side-by-side relation, the improvement comprising a rigid connector plate having a pair of openings through which respective ones of said terminal end portions extend, one portion being xedly secured to the connector plate and the other freely movable axially through its opening, and a band member generally encompassing said other terminal portion and crimped securely thereto, said band member having at least one projecting portion which is engageable with said connector plate upon axial movement of said other terminal portion in a direction toward said connector plate.

References Cited UNITED STATES PATENTS 2,627,014 l/l953 Kolb 219--357 X 2,917,616 12/1959 Thompson 219-347 X 3,017,490 1/1962 McOrlly et al 219-455 X 3,183,341 5/1965 Hanson 219-455 RICHARD M. WOOD, Primary Examiner.

I. G. SMITH, Assistant Examiner. 

